There are no ANSI standards that address color variation in grout.


In part, this is because some colors are more prone to uneven color than others due to pigments and the water used to mix grout. Water conditions vary widely throughout communities and there is no way to regulate this. 


Another factor that influences grout color is the tile itself. It may be impossible to allow grout to cure for best color uniformity and still remove it from the surface of the tile. In other words, grout must be removed from the tile surface before the color has a chance to set. 


It is important to manage your clients expectations regarding grout color. Most grout sample chips are plastic, while the most commonly used grouts are cementitious. It’s not possible for two entirely different materials to be exactly the same color. Plastic grout samples are indicative of the end result. They are not exactly like the plastic sample. Explain this to home owners during the estimating and sales process to avoid misunderstandings. 


If color uniformity is vital, epoxy grouts are often the solution. In existing grout installations, the color can be modified with the use of grout colorants. This is most effective with grout that has not been sealed. Grout that has been washed with oil-based soaps can be very difficult or impossible to re-color. In addition to modifying the color of grout, many grout colorants also function as a sealer.